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-   -   Do I Need a New Fuel Pump? I'm stumped!!!! (http://www.wranglerforum.com/f282/do-i-need-a-new-fuel-pump-im-stumped-145118.html)

stevekaz99 03-08-2012 08:13 PM

Do I Need a New Fuel Pump? I'm stumped!!!!
 
Motor head want-to-be with a TJ problem

My 97 TJ 4.0 since I got it in August never started on the first try. But it started and runs well once it does start. Tonight it almost didn't start at all at the gas station. It took 10 tries to start but it did start and ran fine once it got going.

This is what I have done so far to try to fix this.

Used Injector Cleaner a few times
Used Sea foam in the gas
Cleaned the throttle body
New plugs, Wires, and distributor
New Starter motor
Battery is great as per AutoZone

Tonight the starter sounded strong but it sounded like no fuel was getting to the injectors. It idles good once started with plenty of power.

If I shut down the engine and re-start it starts back up on the first try.

I'm not sure what else to do. I'd be grateful for any advice. The fuel pumps are over $400 dollars.

Steve

TexasT 03-08-2012 11:02 PM

There's a valve in the fuel pump that keeps fuel pressure on the system and allows for fast startup. Jeeps are known for that to valve to leak allowing the pressure to drop and taking a lot of cranking. Try turning on your key and listen for the fuel pump to come on and it should turn off after a few seconds. If it stays on longer it's having to build up pressure. When the pump turns off you should be at pressure and it should start right up. The only way to fix it is replace the fuel pump.

jeepwayoflife 03-09-2012 12:00 AM

Its called the drain back valve fyi

darkproximity 03-09-2012 12:05 AM

did you bother testing any of these systems before buying new parts? if it turns out to be the fuel pump, all that money you spent on everything else would be for naught. That being said there are other things involved with starting your jeep and i wouldn't blame the fuel pump first. Try testing the crank position sensor, and cam position sensor..

burton160w 03-09-2012 08:34 AM

Check the pressure at the fuel lines. Grab a fuel pressure testing kit (free w/ deposit at AutoZone and Advanced Auro) and check the Shrader valve. It's located in the engine bay on the driver side on the fuel rail line. It looks similar to a tire valve stem and you just screw it on (watch out for gas) and check the pressure.

stevekaz99 03-09-2012 03:05 PM

Quote:

Originally Posted by darkproximity (Post 2120093)
did you bother testing any of these systems before buying new parts? if it turns out to be the fuel pump, all that money you spent on everything else would be for naught. That being said there are other things involved with starting your jeep and i wouldn't blame the fuel pump first. Try testing the crank position sensor, and cam position sensor..


The Starter was definitely in need of replacing. It needed a hammer swing to start. The plugs, wires, and distributor were all very old, stock maybe. So I don't regret replacing them.

How do I test the crank position sensor, and cam position sensor?

Thanks for the advice, I am trying to do as much on my own as I can. Much appreciated.

stevekaz99 03-09-2012 03:07 PM

Quote:

Originally Posted by burton160w (Post 2120639)
Check the pressure at the fuel lines. Grab a fuel pressure testing kit (free w/ deposit at AutoZone and Advanced Auro) and check the Shrader valve. It's located in the engine bay on the driver side on the fuel rail line. It looks similar to a tire valve stem and you just screw it on (watch out for gas) and check the pressure.


I'm going to do this. Do you know if the TJ has a Check valve (drain back valve) outside the fuel tank?

stevekaz99 03-09-2012 03:09 PM

Quote:

Originally Posted by TexasT (Post 2119944)
There's a valve in the fuel pump that keeps fuel pressure on the system and allows for fast startup. Jeeps are known for that to valve to leak allowing the pressure to drop and taking a lot of cranking. Try turning on your key and listen for the fuel pump to come on and it should turn off after a few seconds. If it stays on longer it's having to build up pressure. When the pump turns off you should be at pressure and it should start right up. The only way to fix it is replace the fuel pump.

This does work. But instead of three tries it cuts it down to one or two tries.

stevekaz99 03-09-2012 03:18 PM

So It could be the fuel pump, crank position sensor, CAM position sensor, or the drain back valve.

If it does turn out I need to replace the Fuel Pump (aka Fuel Sending Unit) does anyone know a good place to get it? Is see it listed for $400 plus.

My TJ is not my primary vehicle so I have been willing to take on riskier projects with it. I am very much an amateur but you have to start some place.

Again, thank you all for help. 80% of what I learned about fixing my TJ is from this forum.

Thanks,

Steve

Zinger 03-09-2012 03:33 PM

Check around for pricing. I see Rock Auto with options from $110 to $370 (Bosch.)

Here's a link for troubleshooting fuel delivery - keep in mind it's provided by a company that makes/sells fuel parts:

http://www.airtexproducts.com/AIRTEX...tex_TTS_09.pdf

I have the same problem - I just let it pump up for 20 seconds.

stevekaz99 03-09-2012 03:46 PM

The jeep expert at AutoZone thinks it might be the Coolant Temp Sensor.

jetskier111 03-09-2012 09:08 PM

Fuel pump, mine is doing the same thing and I have changed everything out (plugs, starter, bettery).

The anti drain back and all that junk are in tank- you have to drop it to change it. At least thats what I interpreted from the diagrams at NAPA. My TJ starts after doing the 3x on/off key trick. Im just rolling with it that way until it truly dies.

Good luck

stevekaz99 03-26-2012 04:01 PM

Problem solved. Fuel Pump was going. After the new $475 pump was put in I was good to go again. Painful repair I have to say.

My mechanic said he would only use this pump.

Thank you all for the helpful advice.


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